\documentclass{article}

\begin{document}
\begin{tabular}{|c|c|c|c|c|}
	\hline
	A & 1                      & \multicolumn{2}{c|}{2} &       \\ \hline
	B & \multicolumn{2}{c|}{2} & 1                      &       \\
	\hline
	a & b                      & c                      & d & e \\
	\hline
\end{tabular}

\bigskip

\begin{tabular}{|c|c|c|c|c|}
	\hline
	A     & 1                      & \multicolumn{2}{c|}{2} &     \\ \hline
	B     & \multicolumn{2}{c|}{2} & 1                      &     \\
	\hline
	\omit &                        &                        &   &
\end{tabular}

\end{document}
